Urea → (2,5-Dioxo-imidazolidin-4-ylidene)-ethoxy-acetic acid ethyl ester

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Reaction Steps

A mixture of diethyl 2-ethoxy-3-oxo-succinate (55.86 g, 1 eq) and urea (14.41 g, 1 eq.) was refluxed for 2.5 h in 1 M HCl—AcOH (1200 ml, 5 eq.) and allowed to become cool. The cooled mixture was evaporated to dryness. The residues were dissolved in MeOH, heated aside for crystallization. After crystallization, the precipitates were filtered to give a product which was an off-white solid (15.11 g, 27.5%).

Provenance & Evidence